Sheet bending brakes are used for bending and cutting sheets of metal or vinyl work pieces, such as those used for siding on buildings. The sheet bending brake operates by clamping the work piece between opposing clamping surfaces, and using a hinged bending arm to bend the work piece.
Actuation of the clamping system is controlled by rotation of a locking bar. The locking bar is rotatable relative to a frame member about a longitudinal axis of the locking bar. A pivoting arm is rotatably attached to the frame member, and defines an upper clamping surface for engaging the work piece. The pivoting arm is connected to the locking bar via a pivot link. The pivot link is rotatable relative to both the locking bar and the pivot arm. Rotation of the locking bar moves the pivot link, which in turn moves the pivoting arm between an open position and a clamping position.
The pivot link must be adjustable to provide the appropriate clamping force and accommodate different material thicknesses of the work piece. Additionally, the pivot link must be durable so as not to yield or bend under the forces generated during the clamping process.